Pat Rafter hailed Nick Kyrgios as a Davis Cup star of the future after the teenager fell agonisingly short of a dream debut.

Kyrgios, 18, earned a surprise doubles call-up in Australia's World Group playoff against Poland in Warsaw on Saturday.

And he looked right at home in the high-pressure team environment as he and Chris Guccione fell in five sets on clay to specialist doubles duo Marcin Matkowski and Mariusz Fyrstenberg.

Australia's 2-0 advantage from day one allowed team captain Rafter to hand Kyrgios his debut in a live rubber, a tactical move designed to save Lleyton Hewitt's legs for the reverse singles.

While Kyrgios was gutted at missing an early chance to seal Australia's long-awaited return to the competition's top tier, Rafter hailed his performance as "one of the most positive experiences I've seen."

"We've got one of the great Davis Cup players coming up right now," Rafter said after the 5-7, 6-4, 6-2, 6-7 (7/5), 6-4 loss.

"What I saw today is exactly what I want to see in any young kid coming up."

Kyrgios was a late inclusion in Australia's four-man team, replacing Marinko Matosevic on match eve.

Australia can finish the job against Poland if Bernard Tomic or Hewitt win one of Sunday's reverse singles matches.

Should they do so, Kyrgios looks set to figure in the World Group campaign next year.

With Thanasi Kokkinakis also among the world's leading juniors, Rafter said Australia had two of the best young players in the world coming through.

Kyrgios, who marked his senior grand slam debut by beating Radek Stepanek at the French Open, said his experience in Poland was one he would never forget.

"It hurts to lose in best of five sets but I thought there was some really good things we did out there and a lot of room for improvement," Kyrgios said.

"I'm just excited for tomorrow and helping to get our guys over the line and hopefully next time I can get one for the team."